Significant advances in recent years in the reduction in physical size and cost of electronic components have resulted from improvements in techniques for the manufacture of microelectronic circuits, e.g. microlithography. Microlithography, generally, comprises applying a film of a radiation-sensitive polymeric material, i.e. a resist medium, to one surface of a substrate, irradiating certain portions of the film with, e.g. ultraviolet light, an electron beam, X-rays or the like, and developing the film with a solvent to remove solubilized portions thereof. In the instance of a positive resist, irradiation causes the resist medium to become more soluble in the developer solvent. The resist medium remaining on the surface of the substrate is then employed as a protective mask to facilitate the selective etching or other treatment of the exposed portions of the substrate.
Etching of the substrate may be conventionally carried out by chemical treatment or by plasma discharge. Plasma etching, generally, affords finer resolution than chemical etching and is additionally advantageous in that it is free of the pollution and handling problems inherent in the use of chemical etchants. Many resist materials, however, cannot withstand plasma discharge and are eroded along with the substrate resulting in loss of pattern resolution. Therefore, chemical etching is more commonly used in spite of the aboved-named disadvantages.
There is a continuing search for polymeric materials with increased sensitivity to irradiation to achieve higher resolution in answer to the demand for ever-finer circuitry. The positive electron beam recording media provided in accordance with this invention possesses increased sensitivity, good adherence to most substrates and good development latitude. The recording media of this invention further unexpectedly possesses excellent resistance to oxygen plasma etching.